@Idiott22   Look around at all the posts in this forum.  Almost all of them are about this exact issue.  Here is the official explanation.

Unfortunately this does not work. I have cleared website data, cookies, cache, etc. None of the things mentioned in this link work. I sign in, the address changes to “sign in“ then immediately changes to “sign out“ and asks me to login again. Infinite Loop. Please advise on a working solution. Emphasis on working.

I'm having the same issue that a lot of people are having and it's been going on for a couple of months now. It makes me sign in every morning and when I put my password in it says I've reached my limit for unsuccessful sign-in attempts, after one attempt, so I have to go through the whole changing password processes which is quite annoying. After changing my password several times I finally decided just to click on Forgot Password and it takes me through the process but I put in my old password and it thinks it's new and says I've successfully updated my password. Why do I have to go through this every single day in order to read my email? Not to mention that I then have to go through putting my "new" password in on my phone to get my emails. Come on AT&T, or Yahoo, or whoever's in charge of your email system! Get this issue fixed!!! It's been going on way too long!

What is going on at AT&T?  For the past two months, logging into emails results in error messages, requirements to change passwords, and then showing a person "signed in" on the login screen only to come back with the message being logged out after clicking to open the mails.    I've changed passwords and have been going back and forth with this for weeks.  One day everything works fine and I can move between my sbcglobal.net and Yahoo emails and then the next day, I'm back to the crazy messages saying I've logged in too many times (when it was only once) and I go in circles completing the AT&T requests only to end up with no access.  This crazy bouncing to continually log me out is the latest nonsense.   Obviously this is an ongoing problem based on the comments posted.  Why isn't AT&T addressing the issue?